Device for separation and feeding of sheets of a recording carrier

ABSTRACT

For separation and feeding of sheets of the recording carrier, these sheets are supplied stacked in a cassette. An advance head ( 18 ) sits on the stack with advance rollers ( 20 ), which is mounted on the free end of a pivotable arm ( 22 ). In order to be able to insert the cassette accommodating the stack and remove it, a release mechanism is provided that is operated by the cassette. For this purpose, the arm ( 22 ) is mounted on a slide ( 28 ) that is pulled into a release position by tension springs ( 32 ). A pusher ( 44 ) is also provided on the slide ( 28 ) that raises the arm ( 22 ) under spring force. With the cassette, an operating pin ( 58 ) is inserted into the release mechanism. The pin ( 58 ) pushes the slide ( 28 ) against the force of spring ( 32 ), into the operating position of arm ( 22 ) and pushes the pusher ( 44 ) into a position that releases the arm ( 22 ) for lowering onto the stack.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to German Patent Application No. 10 2004 038 971.3, which was filed on Aug. 10, 2004, and is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The invention concerns a device for separation and feeding of sheets of a recording carrier.

BACKGROUND

A device of this type is known from DE 199 50 307 C1. In this known device, the sheets of the recording carrier are supplied in a cassette as an essentially horizontal stack. The cassette is pushed into a receiving space, for example, of an office machine or sheet feeder for an office machine. An advance head with a drivable advance roller lies on the stack, which pushes the uppermost sheet of the stack against a rising slope of the cassette, so that the front edge of the sheet runs up the slope and is separated from the next sheet of the stack. The uppermost sheet so separated is then grasped by the transport device and fed to the office machine, for example, a printer, copier or the like. The advance head is mounted on a free end of an arm, mounted to pivot on an inside wall of the receiving space and extending across the feed direction over the stack. The advance head can follow the diminishing height of the stack by means of the pivotable arm.

In order to be able to pull out the cassette from the receiving space and push it back into the receiving space, for example, when the cassette is changed or is to be loaded with a new stack of sheets, the arm with the advance head must be raised, so that the cassette can be pulled out beneath the advance head and, if necessary, pushed back in again with a new stack beneath the advance head. For this purpose, the known device has a release mechanism with a lift lever. The lift lever is pivoted by the pushed-in cassette, so that it releases the arm and this can be lowered onto the stack. If the cassette is pulled out, it releases the lift lever and this is pivoted under the influence of a spring, so that it raises the arm with the advance head. The release mechanism causes only lifting of the arm with the advance head upward. This lifting is not sufficient in those cases when the advance head is situated right against the slope of the cassette with the advance roller, on which the stack comes in contact with its front edge.

SUMMARY

The underlying object of the invention is to improve a device of the type just mentioned, so that the arm with the advance head guarantees greater free space for removal and insertion of the cassette.

This object can be solved by a device for separation and feeding of sheets of a recording carrier, with a cassette insertable into a receiving space, which receives the sheets in an essentially horizontal stack and has a rising slope, on which the stack lies with its edge facing the free direction, with an arm mounted to pivot on an inside wall of the receiving space and protruding above the stack of the inserted cassette, with an advance head arranged on the free end of the arm, which can be lowered onto the stack by pivoting of the arm and raised from the stack, with at least one advance roller mounted in the advance head, which sits on the uppermost sheet of the stack when the advance head is lowered and can be driven, in order to push the uppermost sheet up for separation on the slope, and with a release mechanism that raises the arm from the stack when the cassette is moved from the receiving space, and which is operated by the cassette inserted into the receiving space, in order to release the arm for lowering onto the stack, wherein the arm is mounted to pivot on a slide that is arranged movable on the inside wall essentially parallel to the surface of the stack, and is moved away from the slope by a spring force, a pusher is arranged moveable on a slide, which engages on the arm and is biased by a spring force in a position that raises the arm, and wherein at least one operating protrusion arranged in a cassette acts on the slide during insertion of the cassette and moves it against the spring force against the slope and acts on the slide and moves it against the spring force into the position that releases the arm.

The operating protrusion can be formed as a pin protruding from a cassette in the insertion direction, which acts on the slide and pusher via wedge surfaces. The slide may have a passage opening for the pin, and a wedge surface can be formed in the passage opening, which the pin encounters during insertion into passage opening, in order to move the slide against the spring force. The pin may have a conical tip that penetrates the operating opening and produces the wedge effect for movement of the pusher. The operating opening can be formed in a thrust plate mounted to move on the slide, and which can be made to cover the passage opening of the slide, and the thrust plate can be connected to the pusher via a pivotable lever. The lever can be designed as a two-arm lever and may convert the pushing path of the thrust plate to a larger pushing path of the pusher. The arm, together with a parallel rod, may form a parallel guide for the advance head, the parallel rod can be lengthened beyond its bearing on the slide, and the pusher may engage on this lengthened end of the parallel rod. The lengthened end may pass through an elongated hole of the pusher, may be freely movable in this elongated hole in the release position and can be entrained by the end of the elongated hole when the pusher is moved into the position that raises the arm under the spring force.

In the device according to the invention, the arm with advanced head is mounted to pivot on a slide guided on the inside wall of the receiving space, parallel to the surface of the stack. A pusher is mounted on this slide, which engages on the arm, in order to raise it or release it for lowering. The arm can therefore not only be raised upward by the slide, but can also be moved away from the slope by means of the slide. The slide is then biased by spring force, so that it is moved away from the slope, and the pusher is biased by spring force, so that it raises the arm. If the cassette is pulled out from its operating position in the receiving space, the arm is raised, on the one hand, by the spring-loaded pusher, and moved away from the slope, on the other hand, by the spring-loaded slide. The arm and the advance head come into a position on this account, in which they are reliably moved out fully from the movement path of the cassette and any sheet stack accommodate in the cassette. Unhampered pulling out and reinsertion of the cassette is possible. The cassette has at least one operating protrusion, with which it engages with the release mechanism when the cassette is pushed into its operating position. The operating protrusion, in the first place, moves the slide against the slope, and, in the second place, moves the pusher against its spring load into the position, in which the pusher releases the arm for lowering.

The operating protrusion is preferably designed as a pin arranged on the outside of the cassette facing the insertion direction of the cassette and protrudes from the cassette in this insertion direction. When the cassette reaches its operating position during insertion, this pin penetrates into the slide, during which the axial penetration movement of the pin is converted via a wedge surface into the displacement movement of the slide against its spring bias. The pin acts further during insertion via a wedge surface on the pusher, in order to move it against its spring force.

It is readily apparent that two separate operating protrusions, for example, pins, can be used for displacement of the slide and pusher. In a preferred variant, the same pin is used, both for displacement of the slide and the pusher, during which this pin acts on the slide and pusher in succession during its axial movement.

In an expedient variant, the slide is movable on guide rods. For mounting on the guide rods, the slide has a certain material thickness. The wedge surface is then expediently made on the slide, in which the wedge surface guarantees sufficient displacement movement of the slide, because of the material thickness.

For movement of the pusher, a lever transmission is preferably used, so that a slight axial movement of the pin is converted to a larger displacement path of the pusher. The wedge surface for conversion of the axial path of the pin to the displacement path can be designed for this purpose as a conical tip of the pin.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further explained below by means of a practical example depicted in the drawing. In the drawing:

FIG. 1 schematically depicts the device with the cassette pulled out.

FIG. 2 schematically depicts the device with the cassette insert.

FIG. 3 shows the device with the cassette pulled out, in which only the pin for operation of the cassette is shown.

FIG. 4 shows a view corresponding to FIG. 3 during engagement of the pin in the release mechanism.

FIG. 5 shows a view corresponding to FIG. 3 with the completely inserted cassette.

FIG. 6 shows a view corresponding to FIG. 5, in which the housing of the release mechanism is removed.

FIG. 7 shows the device in the position of FIG. 3, viewed from the outside, in which the housing of the release mechanism is removed.

FIG. 8 shows the device in the position of FIG. 6, viewed from the outside.

FIG. 9 schematically depicts a top view of the device with the cassette pulled out.

FIG. 10 shows a view corresponding to FIG. 9, with the cassette insert.

FIG. 11 shows an outside view of operation of the pusher with the cassette pulled out.

FIG. 12 shows a front view of the device in the position of FIG. 11.

FIG. 13 shows an outside view of operation of the pusher with the cassette inserted.

FIG. 14 shows a view corresponding to FIG. 12, with the cassette inserted.

DETAILED DESCRIPTION

In order to supply an office machine, for example, a printer, copier or the like, with sheets of a recorded carrier, for example, paper sheets, these sheets are supplied in stack 10. The stack 10 of sheets is accommodated essentially horizontally in a cassette 12 that is inserted into the receiving space of the device. The receiving space can be formed in the office machine itself or in a separate sheet feeder that can be mounted or added on to the office machine. Only an inside wall 14 of the receiving space is shown in the drawing.

The cassette 12 has a slope 16 on its front side facing the feed direction of the sheets, which rises at an angle of about 20-25°, with reference to the vertical on the stack surface. The stack 10 lies with its front edge facing the feed direction on this slope 16. An advance head 18 is positioned on the uppermost sheet of stack 10, which engages frictionally with drivable advance rollers 20 on the uppermost sheet of stack 10. The driven advance rollers 20 push the uppermost sheet of stack 10 with its front edge against slope 16, so that the front edge of the uppermost sheet rises on slope 16 and is separated from the next sheet of stack 10, so that it can be fed separately to further transport to the office machine. The advance head 18 is mounted on the free end of an arm 22 that is mounted to pivot on inside wall 14 in a pivot plane parallel to the plane of slope 16. Since the arm 22 is freely pivotable, the advance head 18 lies freely on the uppermost sheet of stack 10 under the weight of the advance head 18 and arm 22 and can follow the changing height of stack 10. The advance rollers 20 are movable in the advance head 18 against a spring force in the plane of stack 10. Owing to arrangement of arm 22 and advance head 18 and the spring bias of the advance rollers 20, these advance rollers 20 lie on the front end of the uppermost sheet in the feed direction and lie against the slope 16 with a certain spring bias, when the advance rollers 20 are not driven.

As is apparent from FIGS. 1 and 2, the cassette 12 is pushed horizontally into the receiving space, perpendicular to inside wall 14. In order to be able to push cassette 12 with a stack 10 into the receiving space or pull the inserted cassette out of the receiving space, the arm 22 with advance head 18 must be raised from stack 12 and cassette 12 far enough, that sufficient free space for removal and insertion of the cassette is formed. FIG. 1 shows the arm 22 raised in this way with advance head 18, in which the cassette 12 is partially withdrawn. FIG. 2 shows the completely inserted cassette 12 with the lowered arm 22 and the advance head 18 sitting on stack 10. In the operating position depicted in FIG. 2, the sheets can be removed separately from stack 10 and fed to the office machine.

It is explained below how arm 22, with advance head 18, is raised automatically according to the invention, when the cassette 12 is removed from the receiving space, and lowered automatically onto stack 10, when the cassette 12 is inserted into the receiving space.

A release mechanism is arranged on the inside wall of the receiving space. The release mechanism is accommodated in a housing 24, fastened with appropriate fastening devices 26 to the inside wall 14 of the receiving space.

A slide 28, guided to move on two guide bars 30, is arranged on housing 24. The guide bars 30 are mounted parallel to each other and at a spacing in housing 24, so that they run parallel to the inside wall 14 and parallel to the surface of stack 10. Tension springs 32 are fastened on one end to slide 28 and on the other end to housing 24 and pull the slide 28 on guide bars 30 in the direction pointing away from slope 16. The arm 22 is mounted to pivot on the surface of slide 28 facing the receiving space by means of an obliquely positioned bearing axis 34, perpendicular to the pivot plane of arm 22. A parallel rod 36 is also arranged beneath arm 22 and parallel to it, which is mounted to pivot with a bearing 38 on slide 28. The parallel rod 36 is pivotable in the same pivot plane as arm 22 and forms, with arm 22, a parallel guide lying in the pivot plane that causes the advance head 18 to be moved up and down parallel during pivoting of arm 22.

Beneath guide rods 30, the slide 28 has a passage opening 40 that passes through slide 28, perpendicular to its plane, i.e., perpendicular to inside wall 14. The passage opening 40 is designed on its inside wall, directed against slope 16 with a wedge surface 42, that is most clearly visible in the depiction of FIGS. 9 and 10. The wedge surface 42 is arranged perpendicular to the plane of stack 10 and sloped, so that the passage opening 40 tapers from its inlet side facing the receiving space for cassette 12 toward the side facing inside wall 14.

A pusher 44 is arranged on the surface of slide 28 facing inside wall 14, which is guided to move on this surface of slide 28 in the pivot plane of arm 22 and parallel rod 36. The pusher 44 has an elongated hole 46 running in its displacement direction, which is penetrated by an end 48 of parallel rod 36, lengthened beyond bearing 38. On the lower end of pusher 44, a tension spring 50 engages, whose other end is fastened to slide 28. The tension spring 50 pulls the pusher 44 into its lower end position. On the lower end of the pusher 44, one arm of a two-arm lever, mounted to pivot on slide 28, is connected. The other arm of lever 52 is connected to a thrust plate 54, guided to move parallel to pusher 44 on the surface of slide 28. The thrust plate 54 has continuous operating openings 56, perpendicular to the plane of slide 28, which can be brought to cover the outlet side of passage opening 40 facing the inside wall 14.

Cassette 12 has, on its outside, which faces the inside wall 14 during insertion of cassette 12 into the receiving space, a pin 58 that protrudes in the insertion direction. The pin is designed essentially cylindrical and has a conically rounded tip 60.

If no cassette 12 is situated in the receiving space or the cassette is only partially inserted into the receiving space, the device assumes the position depicted in FIGS. 3, 7, 9, 11 and 12. The slide 28 is pulled by tension springs 32 on guide rods 30 in the direction opposite the sheet feed direction. Because of this, the arm 22 and advance head 18 mounted on slide 28 are pulled away from slope 16. The tension spring 50 pulls the pusher 44 downward. The end 48 of the parallel rod 36 reaches the upper end of elongated hole 46 and is entrained by the pusher 44 and pulled downward. The parallel rod 36, and with it arm 22, are pivoted up, so that the advance head 18 is raised. A cassette 12, possibly with stack 10, can now be pulled out unhampered from the receiving space by arm 22 with advance head 18, or inserted into the receiving space.

If the cassette 12 is pushed further into the receiving space from the position depicted in FIGS. 3, 7 and 9, the pin 58, with its tip 60, initially reaches passage opening 40 through an opening 62 of housing 24. Since the slide 28 is retracted by the tension springs 32, the tip 60 of pin 58 encounters the sloped wedge surface 42. On further insertion of pin 58 into the passage opening 40, the tip 60 of pin 58 presses against the wedge surface 42 and, in so doing, pushes the slide 28 against the force of tension springs 32, so that the arm 22 mounted on the slide 28 is moved with the advance head 18 against the slope 16. This position is shown in FIG. 4. As soon as the pin 58 has fully penetrated the passage opening, the slide 28 reaches its inserted end position against the slope 16. The tip 60 of pin 58 now encounters the side of slide 29 facing inside wall 15 from the passage opening 40 and enters the operating opening 56 of thrust plate 54. As is apparent in FIG. 11, the operating opening 56 is initially pushed against the passage opening 40, because the tension spring 50 has also moved the thrust plate 54 via lever 52. On further advance of pin 58, its conical tip 60 encounters the operating opening 56. The pin 58, because of the wedge effect of its conical tip 60, moves the thrust plate 54 against the force of tension spring 50, acting via lever 52, until pin 58 has fully penetrated the operating opening 56 and is axially flush with the passage opening 40. This position, with the fully inserted cassette 12, is shown in FIGS. 5, 6, 8, 10, 13 and 14.

In this end position, the thrust plate 54 has pushed slide 54 upward against the force of tension spring 50 via lever 52, and the elongated hole 46 is also pushed upward on this account, so that the end 48 of parallel rod 36 can now move freely in elongated hole 46. The arm 22, with the advance head 18, can now be lowered onto stack 10 of the cassette, freely pivotable under its own weight.

If, during lowering of advance head 18, its advance rollers 20 come in contact with the slope 16 and cassette 12, the advance rollers 20 roll along this slope 16, until they lie on the uppermost sheet of stack 10. In this case, a bias of the springs, acting on the advance rollers 20 in advance had 18, is produced.

The process runs in reverse, when the cassette 12 is removed from the inserted position. During removal of cassette 12, pin 58 is initially pulled out from the operating opening 56 of the thrust plate 54. The thrust plate 54 is released and the tension spring 50 can pull the pusher 44 downward. The pusher 44 then engages on the end 48 of parallel rod 36, pulls this end downward, so that the arm 22, with advance head 18, is raised. On further removal of the cassette 12, the pin 58 is also removed from the passage opening 40 of slide 28. Because of this, slide 28 is also released and the tension springs 52 can pull the slide and, with it, the arm 22 with advance head 18, away from the slope 16, so that the cassette 12 is fully released and can be removed unhampered from the receiving space. 

1. A device for separation and feeding of sheets of a recording carrier, with a cassette insertable into a receiving space, which receives the sheets in an essentially horizontal stack and has a rising slope, on which the stack lies with its edge facing the free direction, with an arm mounted to pivot on an inside wall of the receiving space and protruding above the stack of the inserted cassette, with an advance head arranged on the free end of the arm, which can be lowered onto the stack by pivoting of the arm and raised from the stack, with at least one advance roller mounted in the advance head, which sits on the uppermost sheet of the stack when the advance head is lowered and can be driven, in order to push the uppermost sheet up for separation on the slope, and with a release mechanism that raises the arm from the stack when the cassette is moved from the receiving space, and which is operated by the cassette inserted into the receiving space, in order to release the arm for lowering onto the stack, wherein the arm is mounted to pivot on a slide that is arranged movable on the inside wall essentially parallel to the surface of the stack, and is moved away from the slope by a spring force, a pusher is arranged moveable on a slide, which engages on the arm and is biased by a spring force in a position that raises the arm, and wherein at least one operating protrusion arranged in a cassette acts on the slide during insertion of the cassette and moves it against the spring force against the slope and acts on the slide and moves it against the spring force into the position that releases the arm.
 2. A device according to claim 1, wherein the operating protrusion is formed as a pin protruding from a cassette in the insertion direction, which acts on the slide and pusher via wedge surfaces.
 3. A device according to claim 2, wherein the slide has a passage opening for the pin, and a wedge surface is formed in the passage opening, which the pin encounters during insertion into passage opening, in order to move the slide against the spring force.
 4. A device according to claim 2, wherein the pin has a conical tip that penetrates the operating opening and produces the wedge effect for movement of the pusher.
 5. A device according to claim 4, wherein the operating opening is formed in a thrust plate mounted to move on the slide, and which can be made to cover the passage opening of the slide, and wherein the thrust plate is connected to the pusher via a pivotable lever.
 6. A device according to claim 5, wherein the lever is designed as a two-arm lever and converts the pushing path of the thrust plate to a larger pushing path of the pusher.
 7. A device according to claim 1, wherein the arm, together with a parallel rod, forms a parallel guide for the advance head, the parallel rod is lengthened beyond its bearing on the slide, and wherein the pusher engages on this lengthened end of the parallel rod.
 8. A device according to claim 7, wherein the lengthened end passes through an elongated hole of the pusher, is freely movable in this elongated hole in the release position and is entrained by the end of the elongated hole when the pusher is moved into the position that raises the arm under the spring force.
 9. A device for separation and feeding of sheets of a recording carrier, comprising: a cassette insertable into a receiving space, which receives the sheets in an essentially horizontal stack and has a rising slope, on which the stack lies with its edge facing the free direction, an arm mounted to pivot on an inside wall of the receiving space and protruding above the stack of the inserted cassette, arranged movable on the inside wall essentially parallel to the surface of stack, and is moved away from the slope by a spring force a pusher arranged moveable on a slide, which engages on the arm and is biased by a spring force in a position that raises the arm, an advance head arranged on the free end of the arm, which can be lowered onto the stack by pivoting of the arm and raised from the stack, at least one advance roller mounted in the advance head, which sits on the uppermost sheet of the stack when the advance head is lowered and can be driven, in order to push the uppermost sheet up for separation on the slope, and a release mechanism that raises the arm from the stack when the cassette is moved from the receiving space, and which is operated by the cassette inserted into the receiving space, in order to release the arm for lowering onto the stack, and at least one operating protrusion arranged in a cassette that acts on the slide during insertion of the cassette and moves it against the spring force against the slope and acts on the slide and moves it against the spring force into the position that releases the arm.
 10. A device according to claim 9, wherein the operating protrusion is formed as a pin protruding from a cassette in the insertion direction, which acts on the slide and pusher via wedge surfaces.
 11. A device according to claim 10, wherein the slide has a passage opening for the pin, and wherein a wedge surface is formed in the passage opening, which the pin encounters during insertion into passage opening, in order to move the slide against the spring force.
 12. A device according to claim 10, wherein the pin has a conical tip that penetrates the operating opening and produces the wedge effect for movement of the pusher.
 13. A device according to claim 12, wherein the operating opening is formed in a thrust plate mounted to move on the slide, and which can be made to cover the passage opening of the slide, and wherein the thrust plate is connected to the pusher via a pivotable lever.
 14. A device according to claim 13, wherein the lever is designed as a two-arm lever and converts the pushing path of the thrust plate to a larger pushing path of the pusher.
 15. A device according to claim 9, wherein the arm, together with a parallel rod, forms a parallel guide for the advance head, the parallel rod is lengthened beyond its bearing on the slide, and wherein the pusher engages on this lengthened end of the parallel rod.
 16. A device according to claim 15, wherein the lengthened end passes through an elongated hole of the pusher, is freely movable in this elongated hole in the release position and is entrained by the end of the elongated hole when the pusher is moved into the position that raises the arm under the spring force.
 17. A method for separation and feeding of sheets of a recording carrier, comprising the steps of: providing a cassette insertable into a receiving space, which receives the sheets in an essentially horizontal stack and has a rising slope, on which the stack lies with its edge facing the free direction, providing an arm mounted to pivot on an inside wall of the receiving space and protruding above the stack of the inserted cassette, arranged movable on the inside wall essentially parallel to the surface of stack, and is moved away from the slope by a spring force providing a pusher arranged moveable on a slide, which engages on the arm and is biased by a spring force in a position that raises the arm, providing an advance head arranged on the free end of the arm, which can be lowered onto the stack by pivoting of the arm and raised from the stack, providing at least one advance roller mounted in the advance head, which sits on the uppermost sheet of the stack when the advance head is lowered and can be driven, in order to push the uppermost sheet up for separation on the slope, and providing a release mechanism that raises the arm from the stack when the cassette is moved from the receiving space, and which is operated by the cassette inserted into the receiving space, in order to release the arm for lowering onto the stack, and providing at least one operating protrusion arranged in a cassette that acts on the slide during insertion of the cassette and moves it against the spring force against the slope and acts on the slide and moves it against the spring force into the position that releases the arm.
 18. A method according to claim 17, wherein the operating protrusion is formed as a pin protruding from a cassette in the insertion direction, which acts on the slide and pusher via wedge surfaces, and wherein the slide has a passage opening for the pin, and a wedge surface is formed in the passage opening, which the pin encounters during insertion into passage opening, in order to move the slide against the spring force.
 19. A method according to claim 7, wherein the arm, together with a parallel rod, forms a parallel guide for the advance head, the parallel rod is lengthened beyond its bearing on the slide, and wherein the pusher engages on this lengthened end of the parallel rod.
 20. A method according to claim 19, wherein the lengthened end passes through an elongated hole of the pusher, is freely movable in this elongated hole in the release position and is entrained by the end of the elongated hole when the pusher is moved into the position that raises the arm under the spring force. 